Objective: To evaluate the safety and efficacy of autologous stem cell transplantation (ASCT) for refractory juvenile idiopathic arthritis (JIA). Design: Retrospective analysis of follow up data on 34 children with JIA who were treated with ASCT in nine different European transplant centres. Rheumatological evaluation employed a modified set of core criteria. Immunological reconstitution and infectious complications were monitored at three month intervals after transplantation. Results: Clinical follow up ranged from 12 to 60 months. Eighteen of the 34 patients (53%) with a follow up of 12 to 60 months achieved complete drug-free remission. Seven of these patients had previously failed treatment with anti-TNF. Six of the 34 patients (18%) showed a partial response (ranging from 30% to 70% improvement) and seven (21%) were resistant to ASCT. Infectious complications were common. There were three cases of transplant related mortality (9%) and two of disease related mortality (6%). Conclusions: ASCT in severely ill patients with JIA induces a drug-free remission of the disease and a profound increase in general wellbeing in a substantial proportion of patients, but the procedure carries a significant mortality risk. The following adjustments are proposed for future protocols: (1) elimination of total body irradiation from the conditioning regimen; (2) prophylactic administration of antiviral drugs and intravenous immunoglobulins until there is a normal CD4+ T cell count.

Objective. To assess the safety and efficacy of intensive immunosuppression followed by T celldepleted autologous hematopoietic stem cell transplantation (ASCT) for induction of disease remission in children with refractory progressive juvenile idiopathic arthritis (JIA).Methods. Twenty-two patients with progressive refractory JIA were followed up over a median period of 80 months after pretreatment with intensive immunosuppression followed by ASCT in a multicenter, prospective, phase II clinical trial. Hematopoietic stem cells were harvested from the patients' bone marrow, depleted of T cells, and kept frozen until used for ASCT. Pretreatment of patients consisted of a combination of antithymocyte globulin, cyclophosphamide, and lowdose total body irradiation. Patients were followed up for ASCT-related complications, recovery of hematologic and immune system parameters, and disease outcomes. Conclusion. Intensive immunosuppression followed by ASCT resulted in sustained complete remission or marked improvement in 15 of 22 patients with progressive refractory JIA. The procedure, however, is associated with significant morbidity and risk of mortality due to prolonged and severe depression of T cell immunity. After fatal complications due to MAS were observed in some patients, the protocol was amended in 1999, to ensure less profound depletion of T cells, better control of systemic disease before transplantation, antiviral prophylaxis after transplantation, and slow tapering of corticosteroids. Following these protocol modifications, no additional ASCT-related deaths were observed among the 11 patients who received the modified treatment. Results. Reconstitution of hematologic values toJuvenile idiopathic arthritis (JIA) is a heterogeneous group of pediatric illnesses that share the Supported by grants from the Netherlands Organization for Scientific Research (940-37-004) and the National League against Rheumatism (NR 901).

Objective. Methotrexate (MTX) is the most commonly used disease-modifying antirheumatic drug in juvenile idiopathic arthritis (JIA). Currently, individual response to MTX cannot be reliably predicted. Identification of clinical and genetic factors that influence the response to MTX could be helpful in realizing the optimal treatment for individual patients. Methods. A cohort of 128 JIA patients treated with MTX were studied retrospectively. Eleven clinical parameters and genotypes of 6 single nucleotide polymorphisms in 5 genes related to the mechanism of action of MTX were compared between MTX responders and nonresponders using a multivariate regression analysis. Results. The time from diagnosis to start of MTX treatment, physician's global assessment at baseline, and the starting dose were significantly associated with the response to MTX at 6 months after initiation. Patients with a shorter time from diagnosis to start of MTX and a higher disease activity according to the physician but with a lower MTX dose showed an increased response. The effect of the starting dose on MTX response seemed to be mainly due to the influence of the systemic JIA subtype. The time from diagnosis to start of MTX treatment and physician's global assessment at baseline were highly correlated. Therefore, the precise effect size of each independent variable could not be determined. Conclusion. In children with JIA, the time from diagnosis to start of MTX appears to be an important factor for MTX response. Our results suggest that an earlier start of MTX treatment will lead to an increased response.

We investigated the humoral (antigen-specific immunoglobulin isotypes, IgG subclasses, and avidity maturation) and cellular (antigen-specific in vitro proliferation) immune response in 18 healthy adult volunteers, following a primary and a single booster vaccination with the T-cell dependent neoantigen rabies administered at a 3-months interval. The IgG antibody titer showed a mean 31-fold increase (range 3-154) 4 weeks after the first vaccination and a memory response was observed after booster vaccination, i.e. high IgG titers, switch from IgM to IgG and IgA and increased antibody avidity. All healthy adults showed a rabies-induced proliferative response with a mean stimulation index of 45 (range 3.5-200) after in vitro stimulation of PBMC obtained at 4 weeks after booster vaccination. The results obtained in this study provide a frame of reference for the interpretation of specific immune responses to the T-cell dependent neoantigen rabies in patients suspected of a primary or secondary immunodeficiency. Humoral and cellular immune responses to the rabies neoantigen provide complementary information on the condition of the immune system of an individual. Five patients diagnosed with a combined immunodeficiency were vaccinated using the same protocol and showed a number of abnormalities, either in the humoral or the cellular immune response to the rabies neoantigen.

European Union's Seventh Framework programme.